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Diffserv deployment in the wide area: network design and testing

Diffserv deployment in the wide area: network design and testing. Tiziana Ferrari Italian National Institute for Nuclear Physics ferrari@cnaf.infn.it TF-TANT task force http://www.dante.net/tf-tant/. Overview. Why diffserv? Test programme testbed interim results:

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Diffserv deployment in the wide area: network design and testing

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  1. Diffserv deployment in the wide area: network design and testing Tiziana Ferrari Italian National Institute for Nuclear Physics ferrari@cnaf.infn.it TF-TANT task force http://www.dante.net/tf-tant/ Tiziana Ferrari Diffserv deployment in the wide area: network design and testing

  2. Overview • Why diffserv? • Test programme • testbed • interim results: • classification and marking • policing • scheduling • QoS measurement • services: • VLL Tiziana Ferrari Diffserv deployment in the wide area: network design and testing

  3. Motivation • Why diffserv? • independent of layer 2 technologies • interoperability: • diffserv domains  National Research Networks (NRN) • diffserv region: NRN + 1 diffserv core domain • independent diffserv implementation in each diffserv domain • traffic aggregation • scalability • transparency to the application Tiziana Ferrari Diffserv deployment in the wide area: network design and testing

  4. Motivation (cont) • (some) benefits: • network layer: • VLL service, a potential replacement of ATM permanent connections • resource allocation on congested links • QoS support in/to NRN which are not ATM based • application layer: • QoS support for mission critical applications (RSVP - diffserv) e.g.: good QoS support to client-server distributed applications thanks to traffic aggregation Tiziana Ferrari Diffserv deployment in the wide area: network design and testing

  5. Diffserv and the European network model DS domain DS domain MPLS NRN NRN Non DS capable domain NRN Marking policing scheduling TEN-155 DS domain NRN (marking) shaping NRN DS domain DS domain Tiziana Ferrari Diffserv deployment in the wide area: network design and testing

  6. Overview of test programme • Diffserv • DSCP: class selectors, EF, AF • test of basic QoS features in diffserv platforms • parameter tuning • interoperability • services: definition, implementation, validation through test applications (video streaming, IP telephony, distributed applications) • diffserv and intserv (end-to-end QoS) • diffserv and MPLS • QoS measurement • Policy management Tiziana Ferrari Diffserv deployment in the wide area: network design and testing

  7. Work accomplished (June 99-Oct 99) • network configuration • baseline performance testing • marking • policing: • functionality, token bucket parameter tuning (normal and exceed burst size) with TCP traffic • CB-WFQ (Class Based WFQ): traffic isolation • scheduling: • CB-WFQ: traffic isolation, VLL service in the wide area • SCFQ (Self Clocked Fair Queuing): EF, AF and best-effort Tiziana Ferrari Diffserv deployment in the wide area: network design and testing

  8. Work accomplished (cont) • QoS measurement (ongoing): • parameters: one-way delay and one-way delay variation • LAN and WAN (VLL service implementation and validation) • traffic generators with GPS antennas • NTP • definition of test services: • point to point virtual leased line • one-to-many virtual leased line • resource allocation on congested links • better than best-effort • services for remote instrumentation control (AF) Tiziana Ferrari Diffserv deployment in the wide area: network design and testing

  9. Diffserv test network Uni. Bologna CSELT EPFL Tiziana Ferrari Diffserv deployment in the wide area: network design and testing

  10. LAN layout (example) Tiziana Ferrari Diffserv deployment in the wide area: network design and testing

  11. Equipment • Test workstations (ATM, Ethernet, Fast Ethernet, Giga Ethernet interfaces) • traffic generators (3 SmartBits, Netcom Systems) connected to GPS rx • ATM switch(es) in each test sites • 2 Cabletron Ethernet switches • DS capable routers: • CISCO C7200 and/or C7500 • IBM 2212 and IBM 2216 (in 5 sites, 2 routers per site) Tiziana Ferrari Diffserv deployment in the wide area: network design and testing

  12. Interim Results Tiziana Ferrari Diffserv deployment in the wide area: network design and testing

  13. Classification, marking and policing • Multi-field classification: OK • packet marking: OK • testing of different “exceed actions”: OK • policing (at a configurable rate): • token bucket: parameter tuning for TCP traffic performance optimisation • normal burst • exceed burst Tiziana Ferrari Diffserv deployment in the wide area: network design and testing

  14. Policing: test of exceed actions drop precedence 0 Throughput: SWITCH: 1.20 Mbps DANTE: 0.38 Mbps (drop effect) Tiziana Ferrari Diffserv deployment in the wide area: network design and testing

  15. Policing: TCP burst tolerance • Normal and exceed burst tuning with TCP traffic • single and multiple TCP streams optimum values are functions of the rate R at which traffic is policed, in particular: • normal burst = 0.5 sec * R independently of the platform • exceed burst = 2 * normal burst Tiziana Ferrari Diffserv deployment in the wide area: network design and testing

  16. Policing: TCP burst tolerance (cont) • CISCO platforms • Target rate: 1.25 Mbps Tiziana Ferrari Diffserv deployment in the wide area: network design and testing

  17. Policing: TCP burst tolerance (cont) • IBM platforms (IBM 2212) • Small TCP burst tolerance in a policer can completely starve a TCP stream. • Token bucket depth is function of the rate at which traffic is policed •  tuning needed Tiziana Ferrari Diffserv deployment in the wide area: network design and testing

  18. Policing: TCP burst tolerance (cont) EF behaviour aggregate of TCP traffic, target rate = 163 Kbps (IBM 2212) Tiziana Ferrari Diffserv deployment in the wide area: network design and testing

  19. Policing, two-parameter TB:optimum burst size for different traffic rates IBM 2212 • Small TCP burst tolerance: it can completely starve a TCP stream • optimum token bucket size: function of the policing rate Tiziana Ferrari Diffserv deployment in the wide area: network design and testing

  20. Scheduling and policing:two-parameter TB and premium buffer size Recommendation: token bucket size < premium buffer size (for low packet loss probability) Tiziana Ferrari Diffserv deployment in the wide area: network design and testing

  21. Scheduling: CB-WFQ Scheduling implementation to provide minimum bandwidth guarantees to classes • tested on CISCO platforms - C7200, IOS 12.0(5)T - • class definition: based on class selectors for aggregation  OK • bandwidth allocation: no starvation, dynamic allocation in case of classes which are not fully deploying the capacity guaranteed to them  OK • traffic isolation between EF BA and best-effort: • several combinations of TCP and UDP traffic • variable number of TCP streams (different aggregation degrees) Tiziana Ferrari Diffserv deployment in the wide area: network design and testing

  22. CB-WFQ: set-up Tiziana Ferrari Diffserv deployment in the wide area: network design and testing

  23. CB-WFQ: traffic isolation, 1 TCP stream • Inconsistent results, for some sites TCP throughput < 1.25 Mbps • different ATM burst tolerances on the WAN connections seem seem to be • the cause  traffic isolation on WAN connections can be an issue Tiziana Ferrari Diffserv deployment in the wide area: network design and testing

  24. CB-WFQ: traffic isolation, multiple TCP streams • Overall TCP performance of the behaviour aggregate improves when the • aggregation degree increases • TCP performance of a single connection still low •  problem under investigation Tiziana Ferrari Diffserv deployment in the wide area: network design and testing

  25. Scheduling: Self Clocked Fair Queuing • IBM 2212 • Policy = (traffic profile, validity period, diffserv action) • Diffserv action = (type of marking, queue type, bandwidth) • optimum traffic isolation (tests only with UDP) Premium: 163.8 Kbps guaranteed (8% PPP link bw) Assured: 819.2 Kbps (40% PPP bw) Tiziana Ferrari Diffserv deployment in the wide area: network design and testing

  26. QoS measurement • Resource allocation monitoring • for resource allocation and network dimensioning • performance measurement • passive • active (invasive traffic) • for service validation • to understand the effect on end-to-end performance of buffering in one router or in a chain Tiziana Ferrari Diffserv deployment in the wide area: network design and testing

  27. Parameters • parameters of interest: • one-way delay, requirements: clock synchronisation • GPS based synchronisation • SmartBits (Netcom Systems) • NTP (Network Time Protocol) • NTP client / server hierarchy • one-way delay variation • deployment of inter packet gap at rx and tx • packet loss probability • throughput Tiziana Ferrari Diffserv deployment in the wide area: network design and testing

  28. tx rx SmartBits QoS measurement: 1-way delay and instantaneous delay variation (LAN) Goal : VLL service implementation and validation Metric: Type-P-One-way-Delay (RFC 2679), type-P-one-way-ipdv Variables: • WFQ/SCFQ EF queue depth • packet size • EF queue “weight” • traffic volume Tiziana Ferrari Diffserv deployment in the wide area: network design and testing

  29. One-way delay: average vs packet size Tiziana Ferrari Diffserv deployment in the wide area: network design and testing

  30. Latency in time Tiziana Ferrari Diffserv deployment in the wide area: network design and testing

  31. ipdv (*without* best-effort) Tiziana Ferrari Diffserv deployment in the wide area: network design and testing

  32. ipdv (*with* best-effort) Tiziana Ferrari Diffserv deployment in the wide area: network design and testing

  33. Services • Virtual leased line: • point to point • one to many • capacity allocation on congested links (e.g. US links) • better-than-best-effort (qualitative definition) Tiziana Ferrari Diffserv deployment in the wide area: network design and testing

  34. VLL Tiziana Ferrari Diffserv deployment in the wide area: network design and testing

  35. VLL: implementation Tiziana Ferrari Diffserv deployment in the wide area: network design and testing

  36. Future work • Weighted Random Early Discard (WRED) testing • completion of IBM testing • study of TCP related issues: ACK colouring, TCP and UDP aggregations with AF • interoperability testing (other future platforms: NORTEL, TELEBIT, TORRENT, Linux) • service implementation and validation • diffserv and MPLS • diffserv and intserv • policy management and bandwidth brokerage Tiziana Ferrari Diffserv deployment in the wide area: network design and testing

  37. To know more • Activities of the TF-TANT task force: • http://www.dante.net/tf-tant • Diffserv test programme and interim test results: • http://www.cnaf.infn.it/~ferrari/tfng/ds • QoS measurement test programme: • http://www.cnaf.infn.it/~ferrari/tfng/qosmon Tiziana Ferrari Diffserv deployment in the wide area: network design and testing

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